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Low-permittivity LiLn(pO_(3))_(4)(Ln=La,Sm,Eu)dielectric ceramics for microwave/millimeter-wave communication

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Journal of Advanced Ceramics 2024年第5期13卷 602-620页

作者： Huanrong Tian Xiaohan Zhang Zidong Zhang Yao Liu Haitao wu Key Laboratory for Liquid-Solid Structural Evolution and processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China School of Materials Science and Engineering Shandong UniversityJinan 250061China School of Environmental and Material Engineering Yantai UniversityYantai 264005China

The development of dielectric materials with low permittivity and low loss is a great challenge in wireless *** this study,LiLn(pO_(3))_(4)(Ln=La,Sm,Eu)ceramic systems were successfully prepared using the traditional solid-state method.X-ray diffraction analysis indicated that the LiLn(pO_(3))_(4)ceramics crystallized in a monoclinic structure when sintered at 850–940℃.The characteristic peak shifted to higher angles with variations in the Ln element,which was ascribed to a reduction in the cell *** analysis by structure refinement revealed that the reduction in the cell volume resulted from the decrease in chemical bond lengths and the compression of[LiO_(4)]and[pO_(4)]***,the LiLn(pO_(3))_(4)ceramic system displayed exceptional performance at low sintering temperatures(910–925℃),including a high quality factor(q·f)of 41,607–75,968 GHz,low temperature coefficient of resonant frequency(τ_(f))ranging from−19.64 to−47.49 ppm/℃,low permittivity(ε_(r))between 5.04 and 5.26,and low density(3.04–3.26 g/cm^(3)).The application of phillips–van Vechten–Levine(p–V–L)theory revealed that the increased q·f value of the LiLn(pO_(3))_(4)systems can be attributed to the enhanced packing fraction,bond covalency,and lattice energy,and the stability of τ_(f) was associated with the increase in the bond ***,a prototype microstrip patch antenna using LiEu(pO_(3))_(4) ceramics was *** measurement results demonstrated excellent antenna performance with a bandwidth of 360 MHz and a peak gain of 5.11 dB at a central frequency of 5.08 ***,low-εr LiLn(pO_(3))_(4)ceramic systems are promising candidates for microwave/millimeter-wave communication.

关键词： low permittivity LiLn(pO_(3))_(4) microwave dielectric properties phillips-van Vechten-Levine(p-V-L)theory microstrip patch antenna

Ambarzumyan's Theorem for the Dirac Operator on Equilateral Tree Graphs

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 568-576页

作者： Dong-Jie wu Xin-Jian XU Chuan-Fu YANG Department of Mathematics School of Mathematics and StatisticsNanjing University of Science and TechnologyNanjing 210094China

The classical Ambarzumyan’s theorem states that if the Neumann eigenvalues of the Sturm-Liouville operator-d^(2)/dx^(2)+q with an integrable real-valued potential q on[0,π] are {n^(2):n≥0},then q=0 for almost all x∈[0,π].In this work,the classical Ambarzumyan’s theorem is extended to the Dirac operator on equilateral tree *** prove that if the spectrum of the Dirac operator on graphs coincides with the unperturbed case,then the potential is identically zero.

关键词： dirac operator quantum graph Ambarzumyan’s theorem inverse spectral problem

Supported Atomically Dispersed pd Catalyzed Direct Alkoxylation and Allylic Alkylation

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Chinese Journal of Chemistry 2024年第7期42卷 719-724页

作者： Ruixuan qin Ziwen Chen qingyuan wu Nanfeng Zheng pengxin Liu New Cornerstone Science Laboratory State Key Laboratory for Physical Chemistry of Solid SurfacesCollaborative Innovation Center of Chemistry for Energy Materialsand National&Local Joint Engineering Research Center of Preparation Technology of NanomaterialsCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamenFujian 361005China Innovation Laboratry for Scences and Technoogies of Energy Materials of Fujan province(IKKM) Xiamen Fujian 361102China School of physical Science and Technology Shanghai Tech UniversityShanghai 201210China Fujian Key Laboratory of Rare-earth Functional Materials Fujian Shanhai Collaborative Innovation Center of Rare-earth Functional MaterialsLongyanFujian 366300China

A new approach to allylic alkylation is realized using an atomically dispersed palladium catalyst(pd1/TiO2-EG).Unlike conventional methods that require derivation of substrates and utilization of additives,this method allows for direct allylic alkylation from allylic alcohols,producing H2O as the sole *** catalyst's high efficiency is attributed to the local hydrogen bonding at the or-ganic-inorganic interface(pd-EG interface),facilitating hydroxyl group activation forη3π-allyl complex *** system demonstrates successful direct C—O and C—C coupling reactions with high selectivity,requiring no *** study highlights the potential of supported atomically dispersed catalysts for greener and more efficient catalysis,meanwhile,offers unique insights into the distinct behavior of atomically dispersed catalysts in comparison to homogeneous or nanoparticle-based catalysts.

关键词： Atomically dispersed catalyst Alkylation C—C coupling Organic-inorganic Interface Hydrogen bond Tsuji-Trost reaction Green catalysis

Real-time UAV path planning based on LSTM network

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Journal of Systems Engineering and Electronics 2024年第2期35卷 374-385页

作者： ZHANG Jiandong GUO Yukun ZHENG Lihui YANG qiming SHI Guoqing wu Yong School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710129China The Flight Automatic Control Research Institute of AVIC Xi’an 710065China Military Representative Office of Marine wuhan Bureau in Luoyang Area Luoyang 471000China

To address the shortcomings of single-step decision making in the existing deep reinforcement learning based unmanned aerial vehicle(UAV)real-time path planning problem,a real-time UAV path planning algorithm based on long shortterm memory(Rpp-LSTM)network is proposed,which combines the memory characteristics of recurrent neural network(RNN)and the deep reinforcement learning *** networks are used in this algorithm as q-value networks for the deep q network(DqN)algorithm,which makes the decision of the q-value network has some *** to LSTM network,the q-value network can use the previous environmental information and action information which effectively avoids the problem of single-step decision considering only the current ***,the algorithm proposes a hierarchical reward and punishment function for the specific problem of UAV real-time path planning,so that the UAV can more reasonably perform path *** verification shows that compared with the traditional feed-forward neural network(FNN)based UAV autonomous path planning algorithm,the Rpp-LSTM proposed in this paper can adapt to more complex environments and has significantly improved robustness and accuracy when performing UAV real-time path planning.

关键词： deep q network path planning neural network unmanned aerial vehicle(UAV) long short-term memory(LSTM)

Multiphase Interfacial Regulation Based on Hierarchical porous Molybdenum Selenide to Build Anticorrosive and Multiband Tailorable Absorbers

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Nano-Micro Letters 2024年第1期16卷 85-105页

作者： Tianbao Zhao Zirui Jia Jinkun Liu Yan Zhang Guanglei wu pengfei Yin College of Science Sichuan Agricultural UniversityYa’an 625014People’s Republic of China Institute of Materials for Energy and Environment State Key Laboratory of Bio‑Fibers and Eco‑TextilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071People’s Republic of China College of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071People’s Republic of China

Electromagnetic wave(EMW)absorbing materials have an irreplaceable position in the field of military stealth as well as in the field of electromagnetic pollution *** in order to cope with the complex electromagnetic environment,the design of multifunctional and multiband high efficiency EMW absorbers remains a tremendous *** this work,we designed a three-dimensional porous structure via the salt melt synthesis strategy to optimize the impedance matching of the ***,through interfacial engineering,a molybdenum carbide transition layer was introduced between the molybdenum selenide nanoparticles and the three-dimensional porous carbon matrix to improve the absorption behavior of the *** analysis indicates that the number and components of the heterogeneous interfaces have a significant impact on the EMW absorption performance of the absorber due to mechanisms such as interfacial polarization and conduction loss introduced by interfacial ***,the prepared MoSe_(2)/MoC/pNC composites showed excellent EMW absorption performance in C,X,and Ku bands,especially exhibiting a reflection loss of−59.09 dB and an effective absorption bandwidth of 6.96 GHz at 1.9 *** coordination between structure and components endows the absorber with strong absorption,broad bandwidth,thin thickness,and multi-frequency absorption ***,it can effectively reinforce the marine anticorrosion property of the epoxy resin coating on q235 steel *** study contributes to a deeper understanding of the relationship between interfacial engineering and the performance of EMW absorbers,and provides a reference for the design of multifunctional,multiband EMW absorption materials.

关键词： Interfacial engineering Anticorrosion Multiband Electromagnetic wave absorber

Six million q factor micro fused silica shell resonator with teeth-like tines released by femtosecond laser-assisted chemical etching

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Science China(Technological Sciences) 2024年第6期67卷 1923-1932页

作者： ZHAO Tao SHI Yan LU Kun XI Xiang wu XueZhong XIAO DingBang College of Intelligence Science and Engineering National University of Defense TechnologyChangsha410073China

The quality factor(q factor)is a crucial performance parameter for *** this paper,a novel release method for highquality micro fused silica shell resonators with teeth-like tines with good surface morphology is *** method is based on femtosecond laser-assisted chemical ***,the optimal energy range of femtosecond laser modification is obtained through mechanism ***,the optimal parameters for a straight line and arc pattern are determined by optimizing the average output power,processing speed,and processing *** results demonstrate why edge breakage in rounded corners is easy under different ***,according to these conclusions,the processing is performed on a micro fused silica shell resonator with a q factor exceeding 6 *** addition,subsurface damage is rare throughout the fabrication process,and the surface roughness of the released cross section reaches the nanometer *** improved q factor helps suppress mechanical thermal noise and reduce zero bias and zero bias drift,constituting the primary method for enhancing the performance of the resonant gyroscope.

关键词： micro hemispherical resonator fused silica laser-assisted chemical etching quality factor

Effects of oxygen vacancy on bond ionicity,lattice energy,and microwave dielectric properties of CeO_(2) ceramics with Yb^(3+) substitution

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Journal of Advanced Ceramics 2024年第2期13卷 247-254页

作者： Mingan Shi Shuyang Ma Wangsuo Xia Ying Wang Jinzi Yu Haitao wu School of Materials Science and physics China University of Mining and TechnologyXuzhou 221008China School of Environment and Material Engineering Yantai UniversityYantai 264005China

Novel Yb_(x)Ce_(1-x)O_(2-0.5x)(x=0-0.8)ceramics,designed by replacing Ce^(4+)with Yb^(3+)ions were prepared by conventional oxide reaction,and the structural stability of the cubic fluorite structure was assessed using lattice energy and ionic properties of Ce/Yb-O *** oxygen vacancy caused by unequal substitution,which played a decisive role in bond ionicity and lattice energy,was analyzed experimentally by XpS and also theoretically by first *** Yb_(x)Ce_(1-x)O_(2-0.5x) ceramics maintain a stable cubic fluorite structure when x≤0.47,corresponding to the minimum lattice energy of 4142 kJ/mol with the lowest ionicity as ƒ_(i)=87.57%.For microwave dielectric properties,when the Yb_(x)Ce_(1-x)O_(2-0.5x)(x=0-0.4)ceramics are pure phase,the porosity-corrected permittivity is dependent on the bond *** q×ƒ values are related to the lattice energy and grain *** temperature coefficient of resonance frequency has been analyzed using bond *** the Yb_(x)Ce_(1-x)O_(2-0.5x)(x=0.5-0.8)ceramics are multiple phases,the microwave dielectric properties are associated with the phase composition and grain growth.

关键词： structure stability bond ionicity oxygen vacancy electronic localization function(ELF)

pICOTEES:a privacy-preserving online service of phenotype exploration for genetic-diagnostic variants from Chinese children cohorts

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Journal of Genetics and Genomics 2024年第2期51卷 243-251页

作者： Xinran Dong Yulan Lu Lanting Guo Chuan Li qi Ni Bingbing wu Huijun Wang Lin Yang Songyang wu qi Sun Hao Zheng Wenhao Zhou Shuang Wang Center for Molecular Medicine Children's Hospital of Fudan UniversityShanghai 201102China Key Laboratory of Birth Defects Children's Hospital of Fudan UniversityShanghai 201102China Department of Bioinformatics Hangzhou Nuowei Information Technology Co.LtdHangzhouZhejiang 310000China The Third Research Institute of the Ministry of public Security Shanghai 200031China Xiamen Campus of Children's Hospital of Fudan University XiamenFujian 361006China Institutes for Systems Genetics West China HospitalChengduSichuan 610041China Shanghai putuo people's Hospital Tongji UniversityShanghai 200060China

The growth in biomedical data resources has raised potential privacy concerns and risks of genetic information leakage. For instance, exome sequencing aids clinical decisions by comparing data through web services, but it requires significant trust between users and providers. To alleviate privacy concerns, the most commonly used strategy is to anonymize sensitive data. Unfortunately, studies have shown that anonymization is insufficient to protect against reidentification attacks. Recently, privacy-preserving technologies have been applied to preserve application utility while protecting the privacy of biomedical data. We present the pICOTEES framework, a privacy-preserving online service of phenotype exploration for genetic-diagnostic variants (https://***:3000/). pICOTEES enables privacy-preserving queries of the phenotype spectrum for a single variant by utilizing trusted execution environment technology, which can protect the privacy of the user's query information, backend models, and data, as well as the final results. We demonstrate the utility and performance of pICOTEES by exploring a bioinformatics dataset. The dataset is from a cohort containing 20,909 genetic testing patients with 3,152,508 variants from the Children's Hospital of Fudan University in China, dominated by the Chinese Han population (>99.9%). Our query results yield a large number of unreported diagnostic variants and previously reported pathogenicity.

关键词： privacy protecti on Rare diseases in children Genetic testing Web system Trusted executi on envir onment

quartz-enhanced multiheterodyne resonant photoacoustic spectroscopy

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Light(Science & Applications) 2024年第4期13卷 696-705页

作者： Jiapeng Wang Hongpeng wu Angelo Sampaolo pietro patimisco Vincenzo Spagnolo Suotang Jia Lei Dong State Key Laboratory of quantum Optics and quantum Optics Devices Institute of Laser SpectroscopyShanxi UniversityTaiyuan 030006China. Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China. polySense Lab Dipartimento Interateneo di FisicaUniversity and Politecnico of BariCNR-IFNVia Amendola 17370126 BariItaly

The extension of dual-comb spectroscopy(DCS)to all wavelengths of light along with its ability to provide ultralarge dynamic range and ultra-high spectral resolution,renders it extremely useful for a diverse array of applications in physics,chemistry,atmospheric science,space science,as well as medical *** this work,we report on an innovative technique of quartz-enhanced multiheterodyne resonant photoacoustic spectroscopy(qEMR-pAS),in which the beat frequency response from a dual comb is frequency down-converted into the audio frequency *** this way,gas molecules act as an optical-acoustic converter through the photoacoustic effect,generating heterodyne sound *** conventional DCS,where the light wave is detected by a wavelengthdependent photoreceiver,qEMR-pAS employs a quartz tuning fork(qTF)as a high-q sound transducer and works in conjunction with a phase-sensitive detector to extract the resonant sound component from the multiple heterodyne acoustic tones,resulting in a straightforward and low-cost hardware *** novel qEMRpAS technique enables wavelength-independent DCS detection for gas sensing,providing an unprecedented dynamic range of 63 dB,a remarkable spectral resolution of 43 MHz(or~0.3 pm),and a prominent noise equivalent absorption of 5.99×10^(-6)cm^(-1)·Hz-1/2.

关键词： quartz hardware resonant